RedundantCastUtil#isCastRedundant: skip further checks if cast operand type equals to cast type

Fixes IDEA-194278 "Too weak variable type leads to unnecessary cast" does not detect some cases

java/java-psi-api/src/com/intellij/psi/util/RedundantCastUtil.java

@@ -46,6 +46,8 @@ public class RedundantCastUtil {
 
   public static boolean isCastRedundant (PsiTypeCastExpression typeCast) {
     PsiElement parent = typeCast.getParent();
+    PsiExpression operand = typeCast.getOperand();
+    if (operand != null && operand.getType() != null && operand.getType().equals(typeCast.getType())) return true;
     while(parent instanceof PsiParenthesizedExpression) parent = parent.getParent();
     if (parent instanceof PsiExpressionList) parent = parent.getParent();
     if (parent instanceof PsiReferenceExpression) parent = parent.getParent();

java/java-tests/testData/inspection/castCanBeRemovedNarrowingVariableType/afterIncomplete.java

@@ -0,0 +1,9 @@
+// "Change type of 'list' to 'ArrayList<String>' and remove cast" "true"
+import java.util.*;
+
+class Test {
+  void test() {
+    ArrayList<String> list = new ArrayList<>();
+    list.ensureCapacity();
+  }
+}

java/java-tests/testData/inspection/castCanBeRemovedNarrowingVariableType/beforeIncomplete.java

@@ -0,0 +1,9 @@
+// "Change type of 'list' to 'ArrayList<String>' and remove cast" "true"
+import java.util.*;
+
+class Test {
+  void test() {
+    List<String> list = new ArrayList<>();
+    ((ArrayList<caret><String>) list).ensureCapacity();
+  }
+}